Community-Identified Implementation Strategies for Promoting the Adoption of HIV Self-Testing in a Southern California American Indian community: A Rapid Qualitative Analysis.

HIV incidence increased by 18% between 2015 and 2019 among American Indians (AIs) despite declining rates in other racial/ethnic groups. Culturally-appropriate implementation of prevention programs is needed to address the intersectional conditions contributing to HIV vulnerabilities experienced by AIs. The objectives of this study were to understand factors influencing HIV testing decisions and identify implementation strategies to promote the acceptability of HIV self-testing (HIVST) in a southern California AI community. A total of 15 semi-structured interviews were completed with adult community members of a southern California AI reservation. Analysis used a rapid analytic approach that was guided by the Exploration, Preparation, Implementation, Sustainment (EPIS) framework and expert recommendations for implementing change (ERIC) compilation. Two team members applied a standardized summary template to elucidate implementation determinants and implementation strategies for adopting HIVST. Barriers to HIV testing identified by community members included HIV-related stigma and privacy concerns within their community. Community members expressed positive perceptions of the acceptability of HIVST, with many identifying ease of use and privacy as appealing attributes. Several implementation strategies were suggested for facilitating the adoption of HIVST, including increasing access to tests by mailing kits to community members and increasing demand for kits through media campaigns (e.g., local flyers, social media posts, and booths at tribal events). Community members also recommended discreet packaging of kits and cultural adaptation of accompanying materials (e.g., educational videos featuring community members). The qualitative input from AI community members facilitated identification of implementation strategies that may promote the acceptability and culturally-appropriateness of HIVST.

RESUMEN: Entre 2015 y 2019, la incidencia del VIH entre los indígenas norteamericanos (INs) aumentó un 18%, a pesar de que en otros grupos étnicos y raciales se observaron reducciones. La implementación culturalmente apropiada de programas preventivos es fundamental para abordar las circunstancias interseccionales que contribuyen a la vulnerabilidad al VIH entre INs. Los objetivos de este estudio fueron comprender los factores que influyen en la decisión de hacerse la prueba del VIH e identificar estrategias para fomentar la aceptabilidad de las auto pruebas, en una comunidad de INs en el Sur de California. Se realizaron 15 entrevistas semiestructuradas con los miembros adultos de una reserva situada en el Sur de California. El análisis se realizó utilizando un método cualitativo rápido, basado en el marco Exploration, Preparation, Implementation and Sustainment (EPIS) (español: Exploración, Preparación, Implementación y Sostenimiento) así como una recopilación de sugerencias de expertas en implementación de intervenciones, conocida como ERIC. Dos miembros del equipo de investigación utilizaron una plantilla estandarizada resumida para investigar factores determinantes y estrategias para la adopción de las auto pruebas del VIH. Los miembros de la reserva de INs identificaron el estigma asociado al VIH, así como preocupación por la privacidad entre la comunidad, como barreras para realizarse las pruebas del VIH. Los miembros reaccionaron positivamente a la aceptabilidad de las auto pruebas del VIH, destacándola facilidad del uso y la privacidad asociadas con estas pruebas. También, se sugirieron varias estrategias para facilitar la adopción de las auto pruebas, incluyendo el envío de pruebas a miembros de la comunidad y el aumento de la demanda de pruebas a través de difusión (e.g., folletos, publicaciones en las redes sociales, y puestos en eventos tribales). Los miembros también recomendaron que los empaques de las auto pruebas sean discretos, y que contengan materiales educativos culturalmente apropiados. Las contribuciones cualitativas de la comunidad INs ayudaron identificar estrategias de implementación que pueden fomentar la aceptabilidad de las auto pruebas del VIH en una manera culturalmente apropiada.

Prevalence of HIV/STIs and correlates with municipal characteristics among female sex workers in 13 Mexican cities.

OBJECTIVE: To identify correlates of HIV/STI prevalence among 13 cities with varying sizes of female sex worker (FSW) populations and municipal characteristics in Mexico. MATERIALS AND METHODS: FSWs underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Logistic regression explored variations in HIV/STI prevalence. RESULTS: Among FSWs (n=1 092), prevalence across 13 sites was: HIV: 0.4% (range: 0%-1.4%): syphilis: 7.8% (range: 0%-17.2%); chlamydia: 15.3% (range: 5.7%-32.2%); gonorrhea:2.9% (range 0%-13.8%), and any HIV/STI: 23% (range: 9.9%- 46%). Municipalities with high human development scores and a lower municipal marginalization index had higher odds of combined HIV/STI prevalence. After controlling for sitespecific variability in municipal characteristics, greater risk of HIV/STIs was associated with lower education, having a spouse diagnosed or treated for an STI, unaffordability of condoms, and having non-Mexican clients. CONCLUSIONS: Prevalence of HIV/STIs varies across Mexican municipalities indicating the need for surveillance to identify hotspots for targeted resource allocation.

OBJETIVO: Identificar correlaciones de la prevalencia de VIH / ITS entre 13 ciudades con diferentes tamaños de población de trabajadoras sexuales y características municipales en México. MATERIAL Y MÉTODOS: Las trabajadoras sexuales fueron entrevistadas y recibieron pruebas de VIH, sífilis, gonorrea y clamidia. La regresión logística exploró las variaciones en la prevalencia del VIH/ITS. RESULTADOS: Entre las trabajadoras sexuales (n = 1 092), la prevalencia en 13 sitios fue: VIH: 0.4% (rango: 0-1.4%): sífilis: 7.8% (rango: 0-17.2%); clamidia: 15.3% (rango: 5.7-32.2%); gonorrea: 2.9% (rango 0-13.8%) y cualquier VIH/ITS: 23% (rango: 9.9-46%). Los municipios con altos puntajes de desarrollo humano y menor índice de marginación municipal tuvieron una mayor probabilidad de prevalencia combinada de VIH/ITS. Después de controlar la variabilidad específica del sitio en las características municipales, el mayor riesgo de VIH / ITS se asoció con menor educación, tener un cónyuge diagnosticado o tratado para una ITS, imposibilidad de conseguir condones y tener clientes no mexicanos. CONCLUSIONES: La prevalencia de VIH/ITS varía entre losmunicipios mexicanos, lo que indica la necesidad de una vigilancia para identificar hotspots para la asignación selectiva.

Impact of Public Safety Policies on Human Immunodeficiency Virus Transmission Dynamics in Tijuana, Mexico.

Background: North Tijuana, Mexico is home to many individuals at high risk for transmitting and acquiring human immunodeficiency virus (HIV). Recently, policy shifts by local government impacted how these individuals were handled by authorities. Here we examined how this affected regional HIV transmission dynamics. Methods: HIV pol sequences and associated demographic information were collected from 8 research studies enrolling persons in Tijuana and were used to infer viral transmission patterns. To evaluate the impact of recent policy changes on HIV transmission dynamics, qualitative interviews were performed on a subset of recently infected individuals. Results: Between 2004 and 2016, 288 unique HIV pol sequences were obtained from individuals in Tijuana, including 46.4% from men who have sex with men, 42.1% from individuals reporting transactional sex, and 27.8% from persons who inject drugs (some individuals had >1 risk factor). Forty-two percent of sequences linked to at least 1 other sequence, forming 37 transmission clusters. Thirty-two individuals seroconverted during the observation period, including 8 between April and July 2016. Three of these individuals were putatively linked together. Qualitative interviews suggested changes in policing led individuals to shift locations of residence and injection drug use, leading to increased risk taking (eg, sharing needles). Conclusions: Near real-time molecular epidemiologic analyses identified a cluster of linked transmissions temporally associated with policy shifts. Interviews suggested these shifts may have led to increased risk taking among individuals at high risk for HIV acquisition. With all public policy shifts, downstream impacts need to be carefully considered, as even well-intentioned policies can have major public health consequences.

Factors associated with extrajudicial arrest for syringe possession: results of a department-wide survey of municipal police in Tijuana, Mexico.

BACKGROUND: Mexican law permits syringe purchase and possession without prescription. Nonetheless, people who inject drugs (PWID) frequently report arrest for syringe possession. Extrajudicial arrests not only violate human rights, but also significantly increase the risk of blood-borne infection transmission and other health harms among PWID and police personnel. To better understand how police practices contribute to the PWID risk environment, prior research has primarily examined drug user perspectives and experiences. This study focuses on municipal police officers (MPOs) in Tijuana, Mexico to identify factors associated with self-reported arrests for syringe possession. METHODS: Participants were active police officers aged ≥18 years, who completed a self-administered questionnaire on knowledge, attitudes and behaviors related to occupational safety, drug laws, and harm reduction strategies. Univariable and multivariable logistic regression was used to identify correlates of recent syringe possession arrest. RESULTS: Among 1044 MPOs, nearly half (47.9%) reported always/sometimes making arrests for syringe possession (previous 6mo). Factors independently associated with more frequent arrest included being male (Adjusted Odds Ratio [AOR] = 1.62; 95% Confidence Interval [95% CI] =1.04-2.52; working in a district along Tijuana River Canal (where PWID congregate) (AOR = 2.85; 95%CI = 2.16-3.77); having recently experienced a physical altercation with PWID (AOR = 2.83; 95% CI = 2.15-3.74); and having recently referred PWID to social and health services (AOR = 1.97; 95% CI = 1.48-2.61). Conversely, odds were significantly lower among officers reporting knowing that syringe possession is legal (AOR = 0.61; 95% CI = 0.46-0.82). CONCLUSIONS: Police and related criminal justice stakeholders (e.g., municipal judges, prosecutors) play a key role in shaping PWID risk environment. Findings highlight the urgent need for structural interventions to reduce extra-judicial syringe possession arrests. Police training, increasing gender and other forms of diversity, and policy reforms at various governmental and institutional levels are necessary to reduce police occupational risks, improve knowledge of drug laws, and facilitate harm reduction strategies that promote human rights and community health.

The Spatial-Temporal Pattern of Policing Following a Drug Policy Reform: Triangulating Self-Reported Arrests With Official Crime Statistics.

BACKGROUND: In 2009, Mexico enacted a drug policy reform (Narcomenudeo) designed to divert persons possessing small amounts of illicit drugs to treatment rather than incarceration. To assess reform impact, this study examines the spatial-temporal trends of drug-related policing in Tijuana, Mexico post-enactment. METHOD: Location of self-reported arrests (N = 1,160) among a prospective, community-recruited cohort of people who inject drugs (PWID) in Tijuana (N = 552) was mapped across city neighborhoods. Official police reports detailing drug-related arrests was triangulated with PWID self-reported arrests. Exploratory spatial data analysis examined the distribution of arrests and spatial association between both datasets across three successive years, 2011-2013. RESULTS: In 2011, over half of PWID reported being detained but not officially charged with a criminal offense; in 2013, 90% of arrests led to criminal charges. Official drug-related arrests increased by 67.8% (p <.01) from 2011 to 2013 despite overall arrest rates remaining stable throughout Tijuana. For each successive year, we identified a high degree of spatial association between the location of self-reported and official arrests (p <.05). CONCLUSION: Two independent data sources suggest that intensity of drug law enforcement had risen in Tijuana despite the promulgation of a public health-oriented drug policy reform. The highest concentrations of arrests were in areas traditionally characterized by higher rates of drug crime. High correlation between self-reported and official arrest data underscores opportunities for future research on the role of policing as a structural determinant of public health.

Relationship between a Centers for Disease Control and Prevention expanded HIV testing initiative and past-year testing by race/ethnicity: a multilevel analysis of the Behavioral Risk Factor Surveillance System.

The Centers for Disease Control and Prevention's (CDC) expanded testing initiative (ETI) aims to bolster HIV testing among populations disproportionately affected by the HIV epidemic by providing additional funding to health departments serving these communities. ETI prioritizes testing in clinical settings; therefore, we examined the relationship between state-level ETI participation and past-year HIV testing among a racially/ethnically diverse sample of adult respondents to the 2012 Behavioral Risk Factor Surveillance System who accessed health services within the 12 months prior to being interviewed. Controlling for individual- and state-level characteristics in a multilevel logistic regression model, ETI participation was independently and positively associated with past-year testing, but this association varied by race/ethnicity. Hispanics had higher odds (adjusted odds ratio [AOR]: 1.49; 95% CI: 1.11-2.02) and American Indian/Alaska Natives had lower odds (AOR: 0.66; 95% CI: 0.43-0.99) of testing if they resided in states with (vs. without) ETI participation. State-level ETI participation did not significantly alter past-year testing among other racial/ethnic groups. Prioritizing public health resources in states most affected by HIV can improve testing patterns, but other mechanisms likely influence which racial/ethnic groups undergo testing.

Utilization of Google enterprise tools to georeference survey data among hard-to-reach groups: strategic application in international settings.

BACKGROUND: As geospatial data have become increasingly integral to health and human rights research, their collection using formal address designations or paper maps has been complicated by numerous factors, including poor cartographic literacy, nomenclature imprecision, and human error. As part of a longitudinal study of people who inject drugs in Tijuana, Mexico, respondents were prompted to georeference specific experiences. RESULTS: At baseline, only about one third of the 737 participants were native to Tijuana, underscoring prevalence of migration/deportation experience. Areas frequented typically represented locations with no street address (e.g. informal encampments). Through web-based cartographic technology and participatory mapping, this study was able to overcome the use of vernacular names and difficulties mapping liminal spaces in generating georeferenced data points that were subsequently analyzed in other research. CONCLUSION: Integrating low-threshold virtual navigation as part of data collection can enhance investigations of mobile populations, informal settlements, and other locations in research into structural production of health at low- or no cost. However, further research into user experience is warranted.

Recent HIV Testing Prevalence, Determinants, and Disparities Among U.S. Older Adult Respondents to the Behavioral Risk Factor Surveillance System.

BACKGROUND: Although routine human immune deficiency virus (HIV) testing during health care visits is recommended for most adults, many older adults (i.e., ages 50-64 years) do not receive it. This study identified factors associated with HIV testing in the past 12 months (i.e., recent HIV testing) among US adults in the 3 categories of older adulthood (50-54, 55-59, and 60-64 years) for which routine HIV testing is recommended. METHOD: This was a cross-sectional analysis of data from US older adult respondents to the 2010 Behavioral Risk Factor Surveillance System. We calculated prevalence (proportions) of HIV testing by age category and race/ethnicity. Using multiple logistic regression, we identified predisposing, enabling, and need factors associated with recent HIV testing within and across age categories, by race/ethnicity and controlling for covariates. RESULTS: HIV testing prevalence was low (<5%), varied by race/ethnicity, and decreased with age. Within and across age categories, the odds of testing were highest among blacks (odds ratio [OR], 3.47; 95% confidence interval [CI], 2.82-4.25) and higher among Latinos (OR, 2.06; 95% CI, 1.50-2.84) and the oldest and youngest categories of American Indians/Alaska Natives (OR, 2.48; 95% CI, 1.11-5.55; OR, 2.98; 95% CI, 1.49-5.95) than among whites. Those reporting a recent doctor visit (OR, 2.32; 95% CI, 1.92-2.74) or HIV risk behaviors (OR, 3.50; 95% CI, 2.67-4.59) had higher odds of HIV testing. CONCLUSION: Regardless of risk, the oldest older adults, whites, and older women may forego HIV testing. Doctor visits may facilitate HIV testing. Additional research is needed to understand why eligible older adults seen by providers may not be screened for HIV infection.

Examining the spatial distribution of law enforcement encounters among people who inject drugs after implementation of Mexico's drug policy reform.

In 2009, Mexico decriminalized the possession of small amounts of illicit drugs for personal use in order to refocus law enforcement resources on drug dealers and traffickers. This study examines the spatial distribution of law enforcement encounters reported by people who inject drugs (PWID) in Tijuana, Mexico to identify concentrated areas of policing activity after implementation of the new drug policy. Mapping the physical location of law enforcement encounters provided by PWID (n = 461) recruited through targeted sampling, we identified hotspots of extra-judicial encounters (e.g., physical/sexual abuse, syringe confiscation, and money extortion by law enforcement) and routine authorized encounters (e.g., being arrested or stopped but not arrested) using point density maps and the Getis-Ord Gi* statistic calculated at the neighborhood-level. Approximately half of the participants encountered law enforcement more than once in a calendar year and nearly one third of these encounters did not result in arrest but involved harassment or abuse by law enforcement. Statistically significant hotspots of law enforcement encounters were identified in a limited number of neighborhoods located in areas with known drug markets. At the local-level, law enforcement activities continue to target drug users despite a national drug policy that emphasizes drug treatment diversion rather than punitive enforcement. There is a need for law enforcement training and improved monitoring of policing tactics to better align policing with public health goals.

Evaluating outcome-correlated recruitment and geographic recruitment bias in a respondent-driven sample of people who inject drugs in Tijuana, Mexico.

Respondent-driven sampling's (RDS) widespread use and reliance on untested assumptions suggests a need for new exploratory/diagnostic tests. We assessed geographic recruitment bias and outcome-correlated recruitment among 1,048 RDS-recruited people who inject drugs (Tijuana, Mexico). Surveys gathered demographics, drug/sex behaviors, activity locations, and recruiter-recruit pairs. Simulations assessed geographic and network clustering of active syphilis (RPR titers ≥1:8). Gender-specific predicted probabilities were estimated using logistic regression with GEE and robust standard errors. Active syphilis prevalence was 7 % (crude: men = 5.7 % and women = 16.6 %; RDS-adjusted: men = 6.7 % and women = 7.6 %). Syphilis clustered in the Zona Norte, a neighborhood known for drug and sex markets. Network simulations revealed geographic recruitment bias and non-random recruitment by syphilis status. Gender-specific prevalence estimates accounting for clustering were highest among those living/working/injecting/buying drugs in the Zona Norte and directly/indirectly connected to syphilis cases (men: 15.9 %, women: 25.6 %) and lowest among those with neither exposure (men: 3.0 %, women: 6.1 %). Future RDS analyses should assess/account for network and spatial dependencies.

Cumulative Lifetime Violence and Bacterial Vaginosis Infection in Sexually Transmitted Infections: Findings From a Retrospective Cohort Study Among Black Women at Risk for HIV.

Introduction: Bacterial vaginosis is the most common vaginal condition among women of reproductive age and has been associated with sexually transmitted infections. This study examines the association between cumulative lifetime violence exposure, bacterial vaginosis, and sexually transmitted infections among Black women at risk for HIV. Methods: HIV-negative Black women in a retrospective cohort study (N=230) completed survey questions on cumulative violence (exposure to sexual or physical abuse before age 18 years and exposure to intimate partner violence or sexual violence [partner or other] after age 18 years and past year), bacterial vaginosis (lifetime and past year), and sexually transmitted infection diagnosis (lifetime and past year). Logistic regression models estimated the associations between cumulative violence, bacterial vaginosis, and sexually transmitted infections. Bacterial vaginosis was examined as a moderator in the association between cumulative violence and sexually transmitted infections. Results: Many women reported cumulative violence exposure (40%), lifetime bacterial vaginosis diagnosis (53%), and lifetime sexually transmitted infection diagnosis (73%). Cumulative violence experience was significantly associated with increased adjusted odds of lifetime bacterial vaginosis diagnosis (AOR=1.98; 95% CI=1.10, 3.54). Lifetime bacterial vaginosis diagnosis (AOR=2.76; 95% CI=1.45, 5.22) and past-year bacterial vaginosis diagnosis (AOR=2.16; 95% CI=1.14, 4.10) were significantly associated with increased odds of lifetime sexually transmitted infection diagnosis. Lifetime bacterial vaginosis diagnosis (AOR=2.10; 95% CI=1.19, 3.70) and past-year bacterial vaginosis diagnosis (AOR=3.00; 95% CI=1.70, 5.31) were significantly associated with past-year sexually transmitted infection diagnosis. Lifetime bacterial vaginosis infection significantly increased the odds of lifetime sexually transmitted infection diagnosis with increasing cumulative violence exposure. Conclusions: Our findings support educating and screening Black women who experience cumulative violence for bacterial vaginosis to reduce the risk of untreated bacterial vaginosis and sexually transmitted infections.

Young, Black/African American, and Latino communities are left behind despite legislative efforts in California to reduce HIV/STI disparities.

Objectives: Sexually transmitted infections (STI) have been on the rise in the United States with racial/ethnic minority groups, gay and bisexual men, and youth experiencing the highest STI and HIV infection rates. In 2022, California became the first state in the nation to pass legislation, Senate Bill 306 (SB 306), requiring health care plans to cover the costs of home test kits for STIs, including HIV. This study examines provisions within SB 306 and its potential to reduce STI and HIV disparities among key demographic groups and geographic regions within California. Study design: Ecological cross-sectional study involving 58 California counties. Methods: Descriptive statistics and choropleth maps compared HIV/STI prevalence rates, uninsured rates, demographic composition, and healthcare provider coverage across California counties. Three geographically weighted Poisson regression analyses were conducted to separately examine the association between proportion of uninsured and HIV, gonorrhea, and chlamydia prevalence rates. Results: HIV/STI rates were significantly and positively associated with the proportion of uninsured residents in Central and Southern California counties. These counties had a higher proportion of demographic groups vulnerable to HIV/STI including a large Latino, Black/African American, and younger (age 15-24) population but had a lower rate of healthcare providers with prescription authority for home testing kits, which is a requirement under SB 306. Conclusions: Cutting-edge solutions are needed to stem the rising tide of new STI and HIV infections. While SB 306 is novel and innovative in intent, its coverage gaps will increase disparities and inequities among historically underserved populations.

Detoxification, 12-step meeting attendance, and non-fatal opioid overdoses among a suburban/exurban population with opioid use disorder.

BACKGROUND: Drug overdoses are the leading cause of injury death in the United States with an estimated 105,752 individuals dying from an overdose in the United States in a 12-month period ending October 2021. Given that people who have opioid use disorder (OUD) are at an increased risk of death, it is crucial to assess risk factors associated with opioid overdose to improve interventions. OBJECTIVES: We examine factors associated with non-fatal overdose among a suburban/exurban population with OUD in Southern California. METHODS: Participants were recruited by convenience sampling (n = 355) and were interviewed between November 2017 to August 2018. Participants were eligible for the study if they had a history of pharmaceutical opioid use. RESULTS: A total of 198 (55.8%) participants reported at least one overdose in their lifetime. A total of 229 participants identified as male, 124 identified as female, and 2 identified as non-binary. When controlling for demographic factors, non-oral opioid administration at first opioid use (AOR 2.82, 95% CI 1.52-5.22), having a history of methadone detoxification, (AOR 2.23, 95% CI 1.27-3.91), history of buprenorphine detoxification (AOR 1.77, 95% CI 1.02-3.07), and history of 12 step attendance (AOR 1.89, 95% CI 1.12-3.20) were found to be independently and positively associated with lifetime opioid overdose. CONCLUSIONS: Detoxification with buprenorphine and methadone was found to be associated with having a non-fatal opioid overdose. Buprenorphine and methadone should not be prescribed as a detoxification medication as long-term use of medication for OUD results in better outcomes than medication that is used short-term.

"There Is a Lot of Practice in Not Thinking about That": Structural, Interpersonal, and Individual-Level Barriers to HIV/STI Prevention among Reservation Based American Indians.

American Indians (AI) face significant disparities in HIV/STI morbidity and mortality, and historical, structural, interpersonal, and individual level barriers stymie prevention efforts. The objective of this paper is to examine barriers to HIV/STI prevention among reservation-based AI. We conducted face-to-face qualitative interviews with 17 reservation-based AI community leaders and community members in Southern California on HIV/STI knowledge and attitudes and barriers to prevention. The disruption of traditional coping mechanisms and healing processes were compromised by historical trauma, and this allowed stigmas to exist where they did not exist before. This impacted access to healthcare services and trust in medicine, and is linked to individuals adopting negative coping behaviors that confer risk for HIV/STI transmission (e.g., substance use and sexual behaviors). Most of the participants reported that HIV/STIs were not discussed in their reservation-based communities, and many participants had a misperception of transmission risk. Stigma was also linked to a lack of knowledge and awareness of HIV/STI's. Limited available services, remoteness of communities, perceived lack of privacy, and low cultural competency among providers further hindered the access and use of HIV/STI prevention services. These findings highlight the need to address the historical, structural, and interpersonal factors impacting individual-level behaviors that can increase HIV/STI transmission among reservation-based AIs. Prevention work should build on community strengths to increase HIV/STI knowledge, reduce stigma, and increase access to preventative care while using culturally grounded methodologies.

Perceived Treatment Need and Latent Transitions in Heroin and Methamphetamine Polydrug Use among People who Inject Drugs in Tijuana, Mexico.

People who inject drugs (PWID) in Tijuana, Mexico, use heroin and/or methamphetamine. While polydrug use is associated with HIV risk behavior, less is known about the stability of polydrug use patterns over time and how polydrug use is related to perceived treatment need. Within a cohort of PWID in Tijuana (N = 735) we sought to (1) characterize subgroups of polydrug and polyroute use from baseline to six months; (2) determine the probabilities of transitioning between subgroups; and (3) examine whether self-reported need for help for drug use modified these transition probabilities. Latent transition analysis (LTA) identified four latent statuses: heroin-only injection (38% at both baseline and follow-up); co-injection of heroin with methamphetamine (3% baseline, 15% follow-up); injection of heroin and methamphetamine (37% baseline, 32% follow-up); and polydrug and polyroute users who injected heroin and both smoked and injected methamphetamine (22% baseline, 14% follow-up). Heroin-only injectors had the highest probability of remaining in the same latent status at follow-up. The majority reported great or urgent need for treatment (51%) and these PWID had greater odds of transitioning to a higher-risk status at follow-up, emphasizing the need for evidence-based drug treatment options for PWID.

Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico.

INTRODUCTION AND AIMS: Patterns of polydrug use among people who inject drugs (PWID) may be differentially associated with overdose and unique human immunodeficiency virus (HIV) risk factors. Subgroups of PWID in Tijuana, Mexico, were identified based on substances used, route of administration, frequency of use and co-injection indicators. DESIGN AND METHODS: Participants were PWID residing in Tijuana age ≥18 years sampled from 2011 to 2012 who reported injecting an illicit substance in the past month (n = 735). Latent class analysis identified discrete classes of polydrug use characterised by 11 indicators of past 6 months substance use. Multinomial logistic regression examined class membership association with HIV risk behaviours, overdose and other covariates using an automated three-step procedure in mplus to account for classification error. RESULTS: Participants were classified into five subgroups. Two polydrug and polyroute classes were defined by use of multiple substances through several routes of administration and were primarily distinguished from each other by cocaine use (class 1: 5%) or no cocaine use (class 2: 29%). The other classes consisted primarily of injectors: cocaine, methamphetamine and heroin injection (class 3: 4%); methamphetamine and heroin injection (class 4: 10%); and heroin injection (class 5: 52%). Compared with the heroin-only injection class, memberships in the two polydrug and polyroute use classes were independently associated with both HIV injection and sexual risk behaviours. DISCUSSION AND CONCLUSIONS: Substance use patterns among PWID in Tijuana are highly heterogeneous, and polydrug and polyroute users are a high-risk subgroup who may require more tailored prevention and treatment interventions. [Meacham MC, Roesch SC, Strathdee SA, Lindsay S, Gonzalez-Zuniga P, Gaines TL. Latent classes of polydrug and polyroute use and associations with human immunodeficiency virus risk behaviours and overdose among people who inject drugs in Tijuana, Baja California, Mexico. Drug Alcohol Rev 2018;37:128-136].

Structural factors associated with methamphetamine smoking among female sex workers in Tijuana, Mexico.

INTRODUCTION AND AIMS: Smoking methamphetamine is associated with increased risk of HIV among female sex workers (FSW). The structural context of substance use is an important shaper of individual behaviour; however, structural determinants of methamphetamine use among FSWs are largely unknown. We identified individual, structural and neighbourhood factors associated with smoking methamphetamine among FSWs in the border city of Tijuana, Baja California, Mexico. DESIGN AND METHODS: A prospective cohort of 301 FSWs sampled from indoor and outdoor sex work venues throughout Tijuana participated in quantitative surveys on behaviours and mapping of home and work neighbourhoods across three visits. Multinomial logistic regression using generalised estimating equations identified individual, structural and neighbourhood variables associated with smoking methamphetamine. RESULTS: Methamphetamine use, particularly smoking, was highly prevalent among FSWs. Over half (61%) of FSWs had ever used methamphetamine in their lifetime and at baseline, 38% currently smoked methamphetamine. Smoking methamphetamine daily was associated with living in the red light district [adjusted odds ratio (AOR) = 2.72, 95% confidence interval (CI) = 1.23-6.02] and with perceived homelessness, but only among women in a good financial situation (AOR = 4.08, 95% CI = 1.58-10.50). Smoking methamphetamine less than daily was associated with older age (AOR = 1.06, 95% CI = 1.02-1.10). DISCUSSION AND CONCLUSIONS: Our findings point to the important dynamic between the residential environment and more severe methamphetamine use. FSWs may prioritise the purchase of methamphetamine over stable housing if they have the financial means. Given the high prevalence of smoking methamphetamine among FSWs in Tijuana, drug treatment options, especially for women living in the red light district, are needed.

Predictors of injecting cessation among a cohort of people who inject drugs in Tijuana, Mexico.

INTRODUCTION: Little is known about the cessation of injecting drug use (IDU) among people who inject drugs (PWID) in low and middle-income settings, where access to effective interventions for reducing drug use (e.g., opioid substitution treatment; OST), may be limited. We measured the incidence and identified predictors of IDU cessation among a cohort of PWID in Tijuana, Mexico. METHODS: Data were drawn from 621 participants in Proyecto El Cuete IV, a prospective cohort of PWID recruited in 2011 and interviewed biannually to 2016. A multivariable Extended Cox model was constructed to identify socio-demographic, drug use, risk environment and health-related predictors of IDU cessation (no IDU for ≥six months). RESULTS: 141 participants (23%) reported at least one IDU cessation event during follow-up. The crude IDU cessation rate was 7.3 per 100 person-years (95% Confidence Interval [CI]: 6.2-8.7). IDU cessation was negatively associated with injecting at least daily on average and heroin/methamphetamine co-injection in the past six months, and positively associated with testing HIV positive at baseline, being on methadone maintenance therapy in the past six months, and recent arrest. Concern for personal safety was also independently associated with IDU cessation. CONCLUSIONS: The rate of IDU cessation among PWID in Tijuana was low. These findings underscore the importance of expansion of services including OST to help reduce drug use and facilitate IDU cessation for those who wish to do so. In this setting, interventions addressing individual-level economic barriers as well as broader social and structural barriers to harm reduction services are integral.